本文選題：模塊化多電平換流器　切入點：直流輸電　出處：《浙江大學》2014年博士論文　論文類型：學位論文

【摘要】：模塊化多電平換流器(Modular Multilevel Converter,MMC)作為新一代柔性直流輸電技術(shù)的核心設備,在新能源并網(wǎng)、電力系統(tǒng)互聯(lián)、大城市供電以及海島供電、海上鉆井平臺供電等場合具有廣闊的應用前景。經(jīng)過十幾年的發(fā)展,MMC的研究工作已經(jīng)取得一定進展,但依然尚有許多問題亟待解決,如大規(guī)模MMC的控制系統(tǒng)設計問題、直流雙極短路故障的處理方式,等等。本文在總結(jié)前人研究成果的基礎上,從以下幾個方面對半橋子模塊型MMC進行了深入研究： (1)研究了MMC的基本工作原理,在忽略了MMC各個子模塊開關(guān)過程的基礎上建立了MMC的交直流解耦模型,該模型將MMC等效為相互解耦的交流回路和直流回路兩部分。在直流回路中,將橋臂不平衡電壓進一步分解為固有分量和修正分量兩部分；固有分量在根源上是MMC與交流系統(tǒng)之間的交換功率引起的,而修正分量是通過一定控制策略產(chǎn)生的用以調(diào)節(jié)MMC內(nèi)部特性的電壓分量。 (2)分析了理想工況下MMC的橋臂電流以及子模塊電壓波動的基本成分。在直接調(diào)制法的作用下,深入研究了諧波環(huán)流與子模塊電壓波動通過調(diào)制函數(shù)相互作用的機理；在此基礎上,詳細建立了諧波環(huán)流、內(nèi)部虛擬電動勢以及子模塊電壓波動的數(shù)學模型,尤其重點討論了MMC的2次諧波環(huán)流成分,隨后討論了諧波環(huán)流的主要危害以及治理問題。針對實際運行中可能出現(xiàn)的上、下橋臂不對稱運行工況,分別分析了上、下橋臂阻抗不對稱和子模塊數(shù)不一致對MMC運行帶來的影響。 (3)研究了交流系統(tǒng)對稱情況下MMC-HVDC控制系統(tǒng)的基本構(gòu)成。根據(jù)交直流解耦模型,將換流站級控制系統(tǒng)分割為交流回路控制器、環(huán)流抑制控制器和阻尼控制器三部分。交流回路控制器負責調(diào)節(jié)MMC與交流系統(tǒng)之間的功率交換,環(huán)流抑制控制器負責抑制負序2倍頻環(huán)流,阻尼控制器主要調(diào)節(jié)直流電流的動態(tài)響應過程。 提出了MMC的啟�？刂品桨浮MC的啟動過程分為不控啟動階段和可控啟動階段；討論了限流電阻與最大交流充電電流峰值之間的數(shù)學關(guān)系,為限流電阻的選取提供依據(jù)。將MMC的停機過程分為能量反饋階段和放電階段,所提出的停機方案有助于提高能量利用率、縮短停機時間和降低放電電阻的選取要求。 (4)針對交流系統(tǒng)不對稱情況下MMC-HVDC直流側(cè)電壓的2倍頻波動問題,同時針對傳統(tǒng)直流電壓波動抑制算法存在矩陣奇異的缺陷,提出適用于MMC-HVDC的新型直流電壓波動抑制方法。該方法利用MMC子模塊能夠儲能的特性,在交流側(cè)負序電流被抑制的同時,完全消除了直流電壓的2倍頻波動。建立了靜止坐標系下3相MMC交流回路和直流回路的數(shù)學模型,同時設計了基于內(nèi)模原理的交流回路控制器、環(huán)流抑制控制器和直流電壓波動抑制控制器。 (5)研究了幾種用于平衡MMC子模塊電壓的單級直接均壓法,包含傳統(tǒng)直接均壓法、引入最大電壓偏差控制的直接均壓法和引入保持因子的直接均壓法,重點從開關(guān)頻率和死區(qū)效應兩方面分析了傳統(tǒng)直接均壓法的缺陷。討論了MMC的控制系統(tǒng)架構(gòu)問題,提出適用于大規(guī)模MMC的“主控制單元+閥組控制單元”型控制系統(tǒng)。為了解決單級直接均壓法中子模塊電壓排序耗時的問題,同時為了解決單級直接均壓法給控制系統(tǒng)帶來的通訊壓力,提出了兩級直接均壓法,將一個橋臂的子模塊均壓過程分解為閥組間均壓和閥組內(nèi)均壓兩部分,二者可并行完成。研制了一臺3相41電平MMC實驗樣機,重點介紹了控制系統(tǒng)的軟件和硬件設計情況,為大規(guī)模MMC控制系統(tǒng)的協(xié)調(diào)控制、子模塊的組織與獨立控制等問題提供解決思路。通過動模實驗驗證了：引入最大電壓偏差控制的直接均壓法有效降低了MMC的開關(guān)頻率和死區(qū)效應；所提出的“主控制單元+閥組控制單元”型控制系統(tǒng)是可行的,所提出的兩級直接均壓法是有效的。
[Abstract]:Modular multilevel converter (Modular Multilevel Converter, MMC) as the core equipment of a new generation of HVDC flexible technology, in the new energy grid, power system interconnection, power supply and large city island power supply, offshore drilling platform, power supply etc. has broad application prospects. After ten years of development, the research work of MMC have made some progress, but there are still many problems to be solved, such as large-scale MMC control system design problems, processing method, DC bipolar short-circuit fault and so on. In this paper, based on the results of previous studies, conducted in-depth research from the following aspects of half bridge sub module type MMC:
(1) study on the basic principle of MMC, ignoring the process based MMC sub module switch on the decoupling of the MMC model, the MMC model will be equivalent to the two part of the decoupling circuit and AC DC circuit. In DC circuit, the unbalanced voltage bridge arm is further decomposed into the two part of a natural component and a correction component; component is the inherent power exchange between MMC and AC system caused by the root, and the correction component is the voltage component adjustment MMC internal characteristics through the control strategy used to produce.
(2) the bridge arm current ideal condition of MMC and the basic components of sub module voltage fluctuation is analyzed. The direct modulation method under the action of in-depth study of the mechanism of harmonic circulation and sub module voltage fluctuation through the modulation function of interaction; on this basis, with a harmonic circulation, the mathematical model of virtual internal electric potential and sub module voltage fluctuation, especially focus on the 2 harmonic circulation component of MMC, then discusses the harmonic circulation major hazards and governance problems. Aiming at the possible in the actual operation, under the bridge arm asymmetry of operating condition, were analyzed, under the influence of bridge arm impedance asymmetry and sub module number no consistent operation of MMC brings.
(3) the basic structure of MMC-HVDC control system of symmetry under AC system. Based on the decoupling model, the converter control system is divided into communication loop controller, circulation suppression controller and a damping controller three. AC loop controller is responsible for regulating the power exchange between MMC and AC system, circulation inhibition controller is responsible for negative sequence 2 harmonic circulation, dynamic response of damping controller mainly adjust the DC current.
Put forward the MMC on-off control scheme. The startup process of MMC is divided into control start-up and controllable start-up stage; discusses the limit of the mathematical relationship between flow resistance and maximum AC charging peak current limit, provide the basis for the choice of the flow resistance. The shutdown process of MMC consists of the energy feedback stage and discharge stage. Stop the scheme helps to improve energy efficiency, reduce downtime and reduce discharge resistance selection requirements.
(4) for the 2 frequency fluctuation of the DC side of MMC-HVDC communication system under asymmetric voltage, while the traditional DC voltage fluctuation suppression algorithm of matrix singular defect suppression method is proposed for the new DC voltage fluctuation of MMC-HVDC. This method uses MMC module to characteristics of energy storage, the AC side negative sequence current is inhibition at the same time, the complete elimination of the 2 harmonic voltage fluctuation. Established a mathematical model of 3 phase MMC AC circuit and DC loop in the stationary coordinate system, and the design of AC loop controller based on the internal model principle, circulation inhibition controller and DC voltage fluctuation suppression controller.
(5) studied for several single-stage balanced MMC sub module voltage direct pressure method, including traditional direct pressure method, introducing the maximum voltage deviation control direct pressure method and introducing the direct pressure maintaining factor method, analyzes the shortcomings of the traditional direct pressure method from two aspects of switching frequency and dead time the effect is discussed. The control system architecture of MMC, which is suitable for large-scale MMC "main control unit + valve control unit" type control system. In order to solve the problem of single level direct pressure method of sub module voltage and time consuming, in order to solve the communication pressure single level direct pressure method were brought to the control system. This paper proposes two level direct pressure method, a bridge arm module is divided into pressure groups and pressure valve within the valve pressure two, two can be done in parallel. Developed a 3 phase 41 level MMC experimental prototype, point introduction The software and hardware design of control system for large-scale, coordinated control of MMC control system, and provide the solutions of sub module organization and independent control problem. Through dynamic simulation experiment proves that introducing the maximum voltage deviation control method can effectively reduce the direct pressure of MMC switching frequency and dead time effect; the proposed "the main control unit and control unit type valve control system is feasible, the proposed two level direct pressure method is effective.

【學位授予單位】：浙江大學
【學位級別】：博士
【學位授予年份】：2014
【分類號】：TM721.1

【參考文獻】

相關(guān)期刊論文 前10條

1 章瑋;王宏勝;任遠;胡家兵;賀益康;;不對稱電網(wǎng)電壓條件下三相并網(wǎng)型逆變器的控制[J];電工技術(shù)學報;2010年12期

2 屠卿瑞;徐政;鄭翔;張靜;;一種優(yōu)化的模塊化多電平換流器電壓均衡控制方法[J];電工技術(shù)學報;2011年05期

3 劉鐘淇;宋強;劉文華;;新型模塊化多電平變流器的控制策略研究[J];電力電子技術(shù);2009年10期

4 劉鐘淇;宋強;劉文華;;采用MMC變流器的VSC-HVDC系統(tǒng)故障態(tài)研究[J];電力電子技術(shù);2010年09期

5 李庚銀,呂鵬飛,李廣凱,周明;輕型高壓直流輸電技術(shù)的發(fā)展與展望[J];電力系統(tǒng)自動化;2003年04期

6 李立mg;;特高壓直流輸電的技術(shù)特點和工程應用[J];電力系統(tǒng)自動化;2005年24期

7 管敏淵;徐政;屠卿瑞;潘偉勇;;模塊化多電平換流器型直流輸電的調(diào)制策略[J];電力系統(tǒng)自動化;2010年02期

8 屠卿瑞;徐政;管敏淵;鄭翔;張靜;;模塊化多電平換流器環(huán)流抑制控制器設計[J];電力系統(tǒng)自動化;2010年18期

9 管敏淵;徐政;;模塊化多電平換流器型直流輸電的建模與控制[J];電力系統(tǒng)自動化;2010年19期

10 李強;賀之淵;湯廣福;司德亮;鄭斌毅;殷志良;;新型模塊化多電平換流器空間矢量脈寬調(diào)制方法[J];電力系統(tǒng)自動化;2010年22期

，

本文編號：1600008